1. Field of the Invention
The present invention relates to a device for sending down seat backrests in vehicles.
2. Description of the Prior Art
In the field of vehicles in general, and of vehicles for transporting passengers in particular, devices for sending down seat backrests are known, which are designed to enable the seats themselves to be set in a lowered position, in which the backrests lie on top of a respective seat, and which comprise, as is for example illustrated in the U.S. Pat. No. 3,966,253, two anchoring plates fixed to the vehicle or else to the seat itself, two supporting plates connected to a frame of the backrest itself and hinged to the anchoring plates, and a moving and blocking device, which is set between at least one anchoring plate and the corresponding supporting plate for moving the backrest between an upright position and the lowered position and for blocking the backrest itself in the upright position.
In the U.S. patent mentioned above, the moving and blocking device comprises an actuation lever and a series of return plates, which are connected to one another and to the actuation lever itself to constrain the supporting plate to the anchoring plate and to release, under the action of the lever, the supporting plate from the anchoring plate, so enabling automatic moving of the backrest as a result of the elastic action of the springs.
The devices for sending down seat backrests of the type described above present a number of drawbacks basically due to their structure, which not only presents a high number of somewhat complex components and requires long production times, but also leads to the onset of mechanical play that can be experienced as unpleasant vibrations of the backrest.